The Stillen systems are hand built on a jig. It is quite possible that the builder didn't have the pipes secured in the jig which caused everything to be slightly off. Aftermarket exhaust vendors really need to be more aware of how exhaust systems are suppose to be designed and fit. It is still beyond me as to why Stillen, Borla, HKS, etc insist on not using y-pipe flex sections. Do they not understand that the flex sections:

1) Reduce NVH
2) Allow the exhaust to move and not stress the manifolds
3) Allow for more consistent fitment

I've never seen an aftermarket exhaust system that fit the way it was suppose to on a car. They all seem to need some adjusting, tweeking, banging, etc. Hell, even my Borla had slight fitment issues which required a little work on the hangers and muffler pipes.

 

Thanks for posting the sound clips! I would VERY MUCH like to hear a GEN1 exhaust clip however.